Robots to Go Spelunking in Martian Caves?

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Scientists are beginning to sketch out plans for NASA's new Mars
rover Curiosity to climb Mount Sharp, but future robots may have
a more direct way to access the planet's history books.

Recent discoveries of "skylights" (pictured here) and lava tubes
on the surface of Mars, as well as the moon, are sparking the
development of robotic probes that can descend into caves and
explore tunnels.

"Geology works in layers, so how many layers can you see? Well,
we know there are sinkholes on Mars. Those sinkholes expose
potentially hundreds of feet of layers, so if you could lower
something down and examine those layers and explore a tunnel
underneath, or anything of that sort, the science that can be
done with that is just phenomenal," Jason Derleth, senior
technology analyst with NASA's Innovative Advanced Concepts
Program, told Discovery News.

Curiosity's landing site inside an ancient impact basin was
selected because of the three-mile high mound of layered rock,
known as Mount Sharp, rising from the crater's floor. Scientists
believe it may be the remains of sediment that once completely
filled the basin. By methodically examining the mountain, layer
by layer, scientists hope to learn if Mars ever had conditions
necessary for life to evolve and for it to be preserved.

An even richer treasure trove may be hidden underground, where
potential habitats would be more shielded from the radiation that
constantly blasts the planet's surface. Underground abodes also
would be better protected from meteorite impacts and would have
more stable temperatures throughout the Martian day-night cycles.

"You just couldn't get better samples than what can be retrieved
from these depths," robotics researcher William "Red" Whittaker,
with Carnegie Mellon University, told Discovery News.

"There's been these dreams of 'Oh, could you drill 2 meters and
get a sample? Could you drill 5 meters and get a sample? Could
you drill 7 meters and get a sample? Could you ever, ever, ever,
ever drill 10 meters and get a sample?' Well, my gosh, how about
you just get out a rope and go down a hole and you can get
samples that are from 50 meters down and everything along the
way?" he said.

Whittaker's firm, Astrobotic Technology, for example is looking
into how a robot would get itself into a cave in the first place.

Rappelling down, like a mountain climber is one option. It is
slow and controlled, but could cause problems if dry, powdery
materials on the cave walls shook lose and rained down on the
robot.

Another option takes advantage of the planet's reduced gravity by
having the robot hop or lob itself down a hole. A third choice is
to string a suspension line across a skylight opening, similar to
a trapeze wire, and have the robot lower itself down the center,
avoiding the cave walls entirely.